1. Field of the Invention
The present disclosure relates to a method and a system for managing a file metadata to provide a continuous data service in spite of address changes of data server and movements of a disk in a large capacity storage system having an asymmetric structure.
This work was supported by the IT R&D program of MIC/IITA. [2007-S-016-01, A Development of Cost Effective and Large Scale Global Internet Service Solution]
2. Description of the Related Art
The general large-scale storage system requires many data servers, and most of mass storage systems are adopting an asymmetric structure that allows a metadata management server to metadata and allows a data server to data, respectively, in order to guarantee high expansibility of the system.
The metadata management server stores and manages the file metadata, which is location information of a data server storing actual file data.
As illustrated in FIG. 1, the related art asymmetric storage system includes n number of user file systems 100 and 101, a metadata management server 110, and n′ number of data servers 120 and 121. The user file systems 100 and 101 request metadata from the metadata management servers 110 and actual file data from the data servers 120 and 121 upon user's request associated with a file. The metadata management server managing the location information of the actual file data checks validity of the request of the user file system, and transmits the requested metadata, e.g., location information of the file data, to the user over network. The data server managing the actual file data hands data of a disk upon the request of such user file systems.
This related art asymmetric storage system stores and manages a data server address by including the location information of the data server in the file metadata. This system has the disadvantage of consuming a lot of time and cost since the administrator must manually change all the data server addresses of the related file metadata with a management tool when the data server address is changed.
When a file metadata is created by using the data server address in an implementation of the related art asymmetric storage system, the data services of all the related files may be interrupted if the data server address is changed due to the address changes in accordance with hardware changes and the change of network topology of the data server, or if a disk is moved from a data server to another data server (e.g., when the administrator intends to provide a data service by using another data server while the data server is shut down for maintenance).